In the related art, displays for displaying images such as a liquid crystal display and an organic EL (EL: Electro-Luminescence) display are widely known.
The organic EL display is configured of self-emitting type light emitting devices arranged in a matrix. The organic EL display has a feature that it can be thinner than the liquid crystal display requiring a back light, and a feature that can realize a high contrast.
As the organic EL display can realize a high contrast, a dark image can be correctly expressed. For this reason, the organic EL display may be used as a display for displaying, for example, an X ray image, a CT (CT: Computed Tomography) image, an MRI (MRI: Magnetic Resonance Imaging) image, or the like. In other words, the organic EL display may be used as a display for diagnostic imaging.
Each light emitting device configuring the organic EL display has a feature that it is deteriorated over time accompanied by emitting light. Therefore, when the same image is displayed on the screen for a long time, the light emitting device emitting light at a relatively high brightness is undesirably deteriorated faster than the light emitting device emitting light at a relatively low brightness. This may generate a variation in a deterioration speed in each light emitting device. When it tries to display on the screen at the same brightness, it is undesirably incapable of displaying at the same brightness. Specifically, when it tries to display on the screen at the same brightness, depending on the variation of the deterioration, characters and symbols may be undesirably viewed as floating. This phenomenon is typically called as “ghosting”.
As the technology relating to the problem, the following Patent Document 1 is disclosed.    Patent Document 1: Japanese Patent Application Laid-open No. 2002-221908